Stability control method of double crystal monochromator based on hybrid control algorithm

The Bragg angle stability of the DCM (double crystal monochromator) in synchrotron radiation facilities is critical for beam position, flux and resolution of hard X-ray beam lines. Generally, the vibration caused by LN2 cooling system is the most critical factor affecting the stability of DCM. In this paper, aiming at the stability of DCM, we propose the stability control method of double crystal monochromator base on hybrid control algorithm. The numerical results show that the stability of the DCM in the pitch direction can be greatly improved by this active vibration control method under LN2 mode. The angular displacement RMS value in the pitch direction decreased from about 358.52 nrad to about 0.071nrad, which decreased by 99.98%. Proposed method is of great significance to the research of ultra-high stability DCM in synchrotron radiation facilities all over the world.